Floating window dimensions should persist after manually resizing

The floating window can be manually resized, but the new width, height, and position of the window does not persist between sessions.
Additionally, moving the floating is not intuitive because you can't grab the top of the window to move it. Moving the window requires clicking and holding the very thin left/right/bottom border.

Recommendations:

- Persist floating window size & position between teleprompter sessions
- Allow moving the floating window by dragging from the top of the window.
- Show the resize NSCursor when hovering over frame edges